Immobilization of cholesterol oxidase and potassium ferricyanide on dodecylbenzene sulfonate ion‐doped polypyrrole film

Dodecylbenzene sulfonate (DBS)‐doped polypyrrole (PPY) conducting polymer films were electrochemically deposited onto the indium‐tin‐oxide (ITO)‐coated glass plates in aqueous medium. The enzyme cholesterol oxidase (ChOx) was immobilized on these DBS–PPY films by a physical adsorption technique. These ChOx‐immobilized DBS–PPY films were characterized by ultraviolet–visible and Fourier transform infrared spectroscopy. The enzyme activity studies indicate that ～40% of ChOx leaches out from the ChOx/DBS–PPY film. The ChOx activity in the ChOx/DBS–PPY film was assayed as a function of cholesterol concentration. The results of amperometric measurements conducted on ChOx/DBS–PPY/ITO film show linearity over the range 2–8 mM of cholesterol solution. The ChOx/DBS–PPY/ITO electrodes exhibit a response time of 30 s and are stable for ～3 months at 4 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3486–3491, 2001     

Phase Transformation and Magnetic Hardening in Isolated FePt Nanoparticles

Isolated monodisperse L1₀ FePt nanoparticles coated by carbon were obtained by adding enough surfactants that decomposed into carbon after the chemical synthesis and postannealing of the A1 FePt nanoparticles. The effect of isolation between FePt nanoparticles on the phase transition temperature and magnetic properties has been studied systematically by thermal, magnetic, and structural characterizations and analyses. It was found that the A1 to L1₀ phase transition temperature is dependent sensitively on the amount of isolation medium. The transition temperature shift reaches 150-200degC from nonisolated particle assemblies to completely isolated particles, which may be attributed to the high activation energy of the phase transformation for the isolated particles.     

Using hyperspectral data to quantify water-quality parameters in the Wabash River and its tributaries,Indiana

A hand-held spectrometer was used to collect above-water spectral measurements for measuring optically active water-quality characteristics of the Wabash River and its tributaries in Indiana. Water sampling was undertaken concurrent with spectral measurements to estimate concentrations of chlorophyll (chl) and total suspended solids (TSS). A method for removing sky and Sun glint from field spectra for turbid inland waters was developed and tested. Empirical models were then developed using the corrected field spectra and in situ chl and TSS data. A subset of the field measurements was used for model development and the rest for model validation. Spectral characteristics indicative of waters dominated by different inherent optical properties (IOPs) were identified and used as the basis of selecting bands for empirical model development. It was found that the ratio of the reflectance peak at the red edge (704 nm) with the local minimum caused by chl absorption at 677 nm was a strong predictor of chl concentrations (coefficient of determination (R²) = 0.95). The reflectance peak at 704 nm was also a good predictor for TSS estimation (R² = 0.75). In addition, we also found that reflectance within the near-infrared (NIR) wavelengths (700–890 nm) all showed a strong correlation (0.85–0.91) with TSS concentrations and generated robust models. Results suggest that hyperspectral information provided by field spectrometer can be used to distinguish and quantify water-quality parameters under complex IOP conditions.     

Effect of compact density and preheating temperature of the Al–Ti–C preform on the fabrication of in situ Mg–TiC composites

Magnesium reinforced in situ TiC particulates was successfully synthesized by utilizing the self-propagating high temperature synthesis (SHS) process. The result showed that preform temperature and compact density have effects on the SHS reaction. It is observed that when the compact density was below 68% of the theoretical density, no SHS reaction occurred. However, with an increase in density from 68 to 72%, the successful thermal explosion reaction was observed in the Mg melt. Besides this, the effect of preheat temperature on the fabrication of Mg/TiC composite was extensively studied and found that the preheat temperature below 300 °C failed to give rise to SHS reaction. However, the preheat temperature of 450, 500, and 550 °C favors the reaction inside the liquid melt, but the temperature of 600 °C leads to the ignition reaction in the preheating furnace itself. SEM and EDX study confirms fine distribution of TiC in the matrix.     

A review on conversion of triglycerides to on‐specification diesel fuels without additional inputs

Dependence on fossil fuels for global energy supply has continued to generate concerns about climate change and sustainable development. It has motivated the search for carbon‐neutral alternative resources for the production of transportation fuels to replace crude oil. Although biodiesels have recently emerged as a close substitute to petrol diesel, their use in compression ignition engines designed to run on petro‐diesel fuels are linked to adverse effects on the engines' performance and life span. This informed efforts at upgrading biodiesel or direct conversion of triglycerides to hydrocarbon mixtures that are identical or similar to that of petro‐diesel through hydrodeoxygenation. Moreover, it seems that commercial methods for the conversion of triglycerides to diesel fuels depends on inputs (methanol and hydrogen) derived from fossil fuels. However, it will be desirable to do so without inputs from fossil fuels. Hence, reaction paths for direct conversion of triglycerides to on‐specification hydrocarbons fuels without hydrogen gas input are discussed and suggested strategies are in cognisance of green chemistry principles. Copyright © 2012 John Wiley & Sons, Ltd.     

Design and development of long-period grating sensors for temperature monitoring

Long Period Gratings (LPGs) have been developed using carbon dioxide laser in a standard optical fibre. LPGs with a periodicity of 600 μm and grating length of 24 mm have been inscribed on standard single mode fibre. Such gratings have been used in designing temperature sensors and temperature is monitored up to 80°C. The sensitivity of such type of sensor is 0·06 nm/°C where as for standard Fibre Bragg Grating (FBG) it is 0·011 nm/°C. The LPG performance is also evaluated after γ-ray irradiation for total dose of 5 KGy and has not shown any effect on transmission spectrum.     

Modeling and simulation of WDM optical networks under traffic control protocols

A proper node architecture design capable to support different network protocol enhances the data transport capability of a wavelength division multiplexed system. In the present paper a simple node architecture model has been developed to simulate the node throughput based on media access control protocols for bursty data traffic of variable time slot duration and data rate. An appropriate mathematical model has been derived to evaluate different types of traffic reservation protocols used in WDM networks. It has been observed that the network performance is well controlled through implemented protocols and network design parameters.     

Deep Learning Approach for Analysis and Characterization of COVID-19

Early diagnosis of a pandemic disease like COVID-19 can help deal with a dire situation and help radiologists and other experts manage human resources more effectively. In a recent pandemic, laboratories perform diagnostics manually, which requires a lot of time and expertise of the laboratorial technicians to yield accurate results. Moreover, the cost of kits is high, and well-equipped labs are needed to perform this test. Therefore, other means of diagnosis is highly desirable. Radiography is one of the existing methods that finds its use in the diagnosis of COVID-19. The radiography observes change in Computed Tomography (CT) chest images of patients, developing a deep learning-based method to extract graphical features which are used for automated diagnosis of the disease ahead of laboratory-based testing. The proposed work suggests an Artificial Intelligence (AI) based technique for rapid diagnosis of COVID-19 from given volumetric chest CT images of patients by extracting its visual features and then using these features in the deep learning module. The proposed convolutional neural network aims to classify the infectious and non-infectious SARS-COV2 subjects. The proposed network utilizes 746 chests scanned CT images of 349 images belonging to COVID-19 positive cases, while 397 belong to negative cases of COVID-19. Our experiment resulted in an accuracy of 98.4%, sensitivity of 98.5%, specificity of 98.3%, precision of 97.1%, and F1-score of 97.8%. The additional parameters of classification error, mean absolute error (MAE), root-mean-square error (RMSE), and Matthew’s correlation coefficient (MCC) are used to evaluate our proposed work. The obtained result shows the outstanding performance for the classification of infectious and non-infectious for COVID-19 cases.